1. Field of the Invention
The present invention relates to a room-temperature-curable organopolysiloxane composition. More specifically, the present invention relates to a room-temperature-curable organopolysiloxane composition that develops a strong adhesion for a variety of substrates, e.g., glass, plastics, metals, and so forth, when cured while in contact with the substrate (contact-curing) and, moreover, that develops this adhesion at an early stage in its cure, wherein this adhesion is highly durable to challenge by hostile ambients, e.g., immersion in hot water and so forth.
2. Background Information
Mayuzumi et al in U.S. Pat. No. 3,837,876, issued Sep. 24, 1974, and Joseph et al in U.S. Pat. No. 4,602,078, issued Jul. 22, 1986, teach organopolysiloxane compositions that are adhesive for a variety of substrates through contact-curing. These compositions consist of hydroxyl-endblocked organopolysiloxane, aminoalkylalkoxysilane/epoxyalkylalkoxysilane mixture or reaction product, and curing catalyst. However, the adherence of the silicone rubbers afforded by the cure of these compositions deteriorates upon exposure to water. In particular, their bonding strength for float glass deteriorates during challenge by hostile ambients, such as immersion in hot water and the like.
Matters in U. S. Pat. No. 3,542,71, issued Nov. 24, 1970, teaches a composition consisting essentially of dimethylpolysiloxane and 0.5 to 10 percent by weight of rosin. These compositions are reported to be paintable. Metters also teaches that the rosin includes unmodified rosin, modified rosin, and rosin derivatives. The rosin derivatives include derivatives made by removal of or reaction with the carboxyl group of abletic acid, such as hydrogenolysis, aminolysis, decarboxylation, and esterification which produces abietic acid esters. Matters teaches that the dimethylsiloxane elastomers can be any kind including those cured by radiation, by the action of heat sensitive curing agents such as peroxides, sulfur, or other free radical generators, by urea or cyanoguanidine, by curing at room temperature by the action of moisture and metal salts of carboxylic acids such as head, manganese, tin, and iron or titanium esters such as butyl titanate, with reactive crosslinking agents such as SiH containing compounds, acyloxy silanes, oxime silanes or alkoxy silanes, and by curing with the reaction of SiH siloxanes and alkenyl substituted siloxanes in the presence of a platinum catalyst.